30 December 2011

Christmas Quizzes (5)

Traditionally, during the week from December 25th to January 1st, ChessBase brings daily chess puzzles selected by John Nunn. The puzzle index page is here. Nunn indicates that the solver should look out for the special moves pawn promotion, en passant capture and castling. All the puzzles deal with them in some way. He also promises some easier puzzles than in previous years. I don't mind them being tough — I am just not too happy when I am to guess (know?) constellations and other stuff related to astronomy. We'll see. So far, solving went smoothly.

For the last time, I have Christmas puzzles for you taken again from the CHESS magazine.

  1Tibor Schönberger  
NĂ©pszava, 1923

  2T. R. Dawson  
White plays and forces stalemate in 4 moves

  3T. R. Dawson  
White takes back his last move and mates in one

4   Place the two kings on the board, so that
a) Black stands legally checkmated.
b) White stands legally checkmated.
c) White can give checkmate in half a move.
d) Black can give checkmate in half a move.

These are the solutions:
11. Na8! Kxb3 2. Rh3+ Kc4/Ka2,4 3. Nb6/Ra3#
1. - b4 2. Na1 ~ 3. Ra5#
21. Bf5! K~ 2. Bxg4 ~ 3. Bh5 ~ 4. g4 and White has stalemated himself!
3White can only retract h2xRg3 and then mate with 1. Qxe2#.
Rectracting h2xPg3 is not legal: the black pawns would have had to capture eight times, but only seven are missing.
If we retract b2xPc3 or b2xRc3, it would have been impossible for the black king to move to the first rank.
We can't retract a king move due to illegal checks.
Retracting a queen or a rook move doesn't leave any possibility to mate in one.
4a) +wKg6, +bKe4
b) +wKb2, +bKd1 (last move was 1.- a1=B#)
c) +wKb4, +bKd4: White already picked up the black pawn and completes the en passant capture d5xe6 e.p.
d) +wKh8, +bKc8: Black completes castling long and puts his rook to d8.

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